Oxygen detectors for detecting oxygen in exhaust gas have been proposed in various forms. One example of the known oxygen detectors is composed of a ceramic substrate and a thick semiconductor membrane adhered onto one surface of the substrate. Such oxygen detectors are, however, unable to withstand the high temperature of the exhaust gas of an internal combustion engine, which is usually 200.degree. to 900.degree. C., and have problems of mechanical strength.
Furthermore, since the semiconductor is temperature dependent, a result of detection must later be compensated for temperature.